Counting of alpha particle tracks on imaging plate based on a convolutional neural network

Imaging plates are widely used to detect alpha particles to track information,and the number of alpha particle tracks is affected by the overlapping and fading effects of the track information.In this study,an experiment and a simulation were used to calibrate the efficiency parameter of an imaging plate,which was used to calculate the grayscale.Images were created by using grayscale,which trained the convolutional neural network to count the alpha tracks.The results demonstrated that the trained convolutional neural network can evaluate the alpha track counts based on the source and background images with a wider linear range,which was unaffected by the overlapping effect.The alpha track counts were unaffected by the fading effect within 60 min,where the calibrated formula for the fading effect was analyzed for 132.7 min.The detection efficiency of the trained convolutional neural network for inhomogeneous ^(241)Am sources(2π emission)was 0.6050±0.0399,whereas the efficiency curve of the photo-stimulated luminescence method was lower than that of the trained convolutional neural network.

Time representation of mitochondrial morphology and function after acute spinal cord injury

Changes in mitochondrial morphology and function play an important role in secondary damage after acute spinal cord injury. We recorded the time representation of mitochondrial morphology and function in rats with acute spinal cord injury. Results showed that mitochondria had an irregular shape, and increased in size. Mitochondrial cristae were disordered and mitochondrial membrane rupture was visible at 2–24 hours after injury. Fusion protein mitofusin 1 expression gradually increased, peaked at 8 hours after injury, and then decreased to its lowest level at 24 hours. Expression of dynamin-related protein 1, amitochondrial fission protein, showed the opposite kinetics. At 2–24 hours after acute spinal cord injury, malondialdehyde content, cytochrome c levels and caspase-3 expression were increased, but glutathione content, adenosine triphosphate content, Na＋-K＋-ATPase activity and mitochondrial membrane potential were gradually reduced. Furthermore, mitochondrial morphology altered during the acute stage of spinal cord injury. Fusion was important within the first 8 hours, but fission played a key role at 24 hours. Oxidative stress was inhibited, biological productivity was diminished, and mitochondrial membrane potential and permeability were reduced in the acute stage of injury. In summary, mitochondrial apoptosis is activated when the time of spinal cord injury is prolonged.

医疗机构工作人员是否需要戴口罩?——基于最佳证据的论述

目的目前关于医疗机构工作人员是否需要戴口罩仍存在较大争议,本研究意在评价和总结针对这一问题的现有最佳证据,以期为临床医务工作人员使用口罩提供参考。方法计算机检索PubMed、Cochrane图书馆、Web of Science、CINAHL、中国知网、万方、维普、中国生物医学文献数据库,指南数据库平台及相关专业学会组织,检索时限为建库至2019年10月27日,以获取相关指南、专家共识、系统评价,应用国际公认的质量评价工具对纳入的证据进行质量评价,汇总现有证据对医疗机构人员是否需要戴口罩这一问题的相关推荐内容。结果共纳入35篇文献,其中6篇指南,27篇专家共识,2篇系统评价,证据质量整体较高。现有证据均推荐使用口罩作为个人防护措施之一,且与不使用呼吸防护设备相比,戴口罩在预防院内感染方面具有明显的优势,并根据不同的应用情景如手术区域、实验室区、产科等提出多项推荐意见。结论现有证据充分认可戴口罩作为个人防护措施之一在医疗机构中预防院内感染的重要作用。但本研究纳入的证据质量仍有一定的局限性。临床医务工作人员应当结合自身工作经验、临床实际情况等因素综合考虑,合理、规范使用口罩。

Epidural Spinal Cord Stimulation Promotes Motor Functional Recovery by Enhancing Oligodendrocyte Survival and Differentiation and by Protecting Myelin after Spinal Cord Injury in Rats

Epidural spinal cord stimulation (ESCS) markedly improves motor and sensory function after spinal cord injury (SCI), but the underlying mechanisms are unclear.Here, we investigated whether ESCS affects oligodendrocyte differentiation and its cellular and molecular mechanisms in rats with SCI. ESCS improved hindlimb motor function at 7 days, 14 days, 21 days, and 28 days after SCI.ESCS also significantly increased the myelinated area at 28days, and reduced the number of apoptotic cells in the spinal white matter at 7 days. SCI decreased the expression of 20,30-cyclic-nucleotide 30-phosphodiesterase (CNPase,an oligodendrocyte marker) at 7 days and that of myelin basic protein at 28 days. ESCS significantly upregulated these markers and increased the percentage of Sox2/CNPase/DAPI-positive cells (newly differentiated oligodendrocytes) at 7 days. Recombinant human bone morphogenetic protein 4 (rh BMP4) markedly downregulated these factors after ESCS. Furthermore, ESCS significantly decreased BMP4 and p-Smad1/5/9 expression after SCI,and rh BMP4 reduced this effect of ESCS. These findings indicate that ESCS enhances the survival and differentiation of oligodendrocytes, protects myelin, and promotes motor functional recovery by inhibiting the BMP4-Smad1/5/9 signaling pathway after SCI.